Sorry, I haven't posted in a while but I thought that I would pass this along. Someone just sent it to me today and I found it helpful and meaningful. Perhaps it will be helpful to some of you as well.
All the best to all of you 
Energy to Spare
Knowing Your Limits
Every human life is defined, to some extent, by limits. No one person is capable of fulfilling every possibility. We are all born with unique aptitudes and sensitivities, and it is these qualities that largely determine the paths we will travel in life. What invigorates, excites, and inspires one individual may exhaust or overwhelm another. When we understand what we as individuals are capable of reasonably handling, we gradually learn to accept that we have control over our wellbeing. Yet determining where our limits lie can be difficult, as it is likely we have been told time and again that the discomfort, fatigue, and stress we felt while engaging in activities outside the range of our comfort zones was all in our heads. If you have never before given thought to the notion of personal limits, creating a list of those tasks and situations that leave you feeling drained can give you insight into your own.
You will know definitively that you are operating within your limits when you have the necessary energy and drive to address your personal and professional commitments. This is not to say you should not push yourself or work to extend the range of your capabilities. The wisdom you gain through dynamic self-examination will give you the tools you need to create an individual life strategy that allows you to achieve your goals without compromising yourself or your needs. The limits you honor by focusing your energy on what you can do rather than what you cannot do will not interfere with your ambitions unless you allow them to interfere. You can thrive within your limits, actively shape your circumstances, and avoid anguish by simply recognizing that certain aspects of life nourish you while others drain you, and doing your best to perceive the fine line between applying yourself diligently and overworking yourself.